Could someone please identify these rocks? Hoping to use them in a saltwater aquarium
closed as off-topic by user12525, trond hansen, Fred, arkaia, Erik Sep 6 at 20:58
This question appears to be off-topic. The users who voted to close gave this specific reason:
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Three layered ones look like either sandstone or limestone with a bit of iron oxides. You can put several droplets of acid and check if they fizz. If they do, that is limestone, but I have seen limestone in that colour only once and think that is more likely to be sandstone.